1. Mow the lawn to about the height of 1.5"-2"
2. Rake up and bag the clippings
3. Aerate the lawn which reduces lawn thatch
4. Add a layer of topsoil especially if the topsoil is too thing such as areas with shallow tree roots. This is optional. However, majority of people do this anyway.

Over-seeding
To properly overseed the lawn, use a spreader. This way the seeds will be evenly spread. The grass seeds need to be kept moist until germination. When watering don't allow the water to puddle or run off as this will wash your seeds away. It is recommended to use a fine spray to avoid a run off. This is a good time to apply a starter fertilizer. Once the grass blades sprout, water it a couple times per day. You can apply a quick-release nitrogen fertilizer after about five weeks.

The best time to overseed lawns in the Greater Toronto Area and Durham Region including Uxbridge is in early September or in the spring (April or May). Successful overseeding will allow you to cover patches in the lawn and have a healthy looking lawn for the summer.